/*
 This file is part of Subsonic.

 Subsonic is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 Subsonic is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with Subsonic.  If not, see <http://www.gnu.org/licenses/>.

 Copyright 2009 (C) Sindre Mehus
 */
package net.nullsum.audinaut.util;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Build;
import android.os.Environment;
import android.util.Log;

import androidx.core.content.ContextCompat;

import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.io.Input;
import com.esotericsoftware.kryo.io.Output;

import net.nullsum.audinaut.domain.Artist;
import net.nullsum.audinaut.domain.Genre;
import net.nullsum.audinaut.domain.Indexes;
import net.nullsum.audinaut.domain.MusicDirectory;
import net.nullsum.audinaut.domain.MusicFolder;
import net.nullsum.audinaut.domain.Playlist;
import net.nullsum.audinaut.service.MediaStoreService;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.InflaterInputStream;

/**
 * @author Sindre Mehus
 */
public class FileUtil {

    private static final String TAG = FileUtil.class.getSimpleName();
    private static final String[] FILE_SYSTEM_UNSAFE = {"/", "\\", "..", ":", "\"", "?", "*", "<", ">", "|"};
    private static final String[] FILE_SYSTEM_UNSAFE_DIR = {"\\", "..", ":", "\"", "?", "*", "<", ">", "|"};
    private static final List<String> MUSIC_FILE_EXTENSIONS = Arrays.asList("mp3", "ogg", "opus", "aac", "flac", "m4a", "wav", "wma");
    private static final List<String> PLAYLIST_FILE_EXTENSIONS = Collections.singletonList("m3u");
    private static final int MAX_FILENAME_LENGTH = 254 - ".complete.mp3".length();
    private static final Kryo kryo = new Kryo();
    private static File DEFAULT_MUSIC_DIR;
    private static HashMap<String, MusicDirectory.Entry> entryLookup;

    static {
        kryo.register(MusicDirectory.Entry.class);
        kryo.register(Indexes.class);
        kryo.register(Artist.class);
        kryo.register(MusicFolder.class);
        kryo.register(Playlist.class);
        kryo.register(Genre.class);
    }

    public static File getEntryFile(Context context, MusicDirectory.Entry entry) {
        if (entry.isDirectory()) {
            return getAlbumDirectory(context, entry);
        } else {
            return getSongFile(context, entry);
        }
    }

    public static File getSongFile(Context context, MusicDirectory.Entry song) {
        File dir = getAlbumDirectory(context, song);

        StringBuilder fileName = new StringBuilder();
        Integer track = song.getTrack();
        if (track != null) {
            if (track < 10) {
                fileName.append("0");
            }
            fileName.append(track).append("-");
        }

        fileName.append(fileSystemSafe(song.getTitle()));
        if (fileName.length() >= MAX_FILENAME_LENGTH) {
            fileName.setLength(MAX_FILENAME_LENGTH);
        }

        fileName.append(".");
        if (song.getTranscodedSuffix() != null) {
            fileName.append(song.getTranscodedSuffix());
        } else {
            fileName.append(song.getSuffix());
        }

        return new File(dir, fileName.toString());
    }

    public static File getPlaylistFile(Context context, String server, String name) {
        File playlistDir = getPlaylistDirectory(context, server);
        return new File(playlistDir, fileSystemSafe(name) + ".m3u");
    }

    public static void writePlaylistFile(Context context, File file, MusicDirectory playlist) throws IOException {
        FileWriter fw = new FileWriter(file);
        BufferedWriter bw = new BufferedWriter(fw);
        try {
            fw.write("#EXTM3U\n");
            for (MusicDirectory.Entry e : playlist.getChildren()) {
                String filePath = FileUtil.getSongFile(context, e).getAbsolutePath();
                if (!new File(filePath).exists()) {
                    String ext = FileUtil.getExtension(filePath);
                    String base = FileUtil.getBaseName(filePath);
                    filePath = base + ".complete." + ext;
                }
                fw.write(filePath + "\n");
            }
        } catch (Exception e) {
            Log.w(TAG, "Failed to save playlist: " + playlist.getName());
        } finally {
            bw.close();
            fw.close();
        }
    }

    public static File getPlaylistDirectory(Context context) {
        File playlistDir = new File(getSubsonicDirectory(context), "playlists");
        ensureDirectoryExistsAndIsReadWritable(playlistDir);
        return playlistDir;
    }

    public static File getPlaylistDirectory(Context context, String server) {
        File playlistDir = new File(getPlaylistDirectory(context), server);
        ensureDirectoryExistsAndIsReadWritable(playlistDir);
        return playlistDir;
    }

    public static File getAlbumArtFile(Context context, MusicDirectory.Entry entry) {
        if (entry.getId().contains(ImageLoader.PLAYLIST_PREFIX)) {
            File dir = getAlbumArtDirectory(context);
            return new File(dir, Util.md5Hex(ImageLoader.PLAYLIST_PREFIX + entry.getTitle()) + ".jpeg");
        } else {
            File albumDir = getAlbumDirectory(context, entry);
            File artFile;
            File albumFile = getAlbumArtFile(albumDir);
            File hexFile = getHexAlbumArtFile(context, albumDir);
            if (albumDir.exists()) {
                if (hexFile.exists()) {
                    hexFile.renameTo(albumFile);
                }
                artFile = albumFile;
            } else {
                artFile = hexFile;
            }
            return artFile;
        }
    }

    private static File getAlbumArtFile(File albumDir) {
        return new File(albumDir, Constants.ALBUM_ART_FILE);
    }

    private static File getHexAlbumArtFile(Context context, File albumDir) {
        return new File(getAlbumArtDirectory(context), Util.md5Hex(albumDir.getPath()) + ".jpeg");
    }

    public static Bitmap getAlbumArtBitmap(Context context, MusicDirectory.Entry entry, int size) {
        File albumArtFile = getAlbumArtFile(context, entry);
        if (albumArtFile.exists()) {
            final BitmapFactory.Options opt = new BitmapFactory.Options();
            opt.inJustDecodeBounds = true;
            BitmapFactory.decodeFile(albumArtFile.getPath(), opt);
            opt.inPurgeable = true;
            opt.inSampleSize = Util.calculateInSampleSize(opt, size, Util.getScaledHeight(opt.outHeight, opt.outWidth, size));
            opt.inJustDecodeBounds = false;

            Bitmap bitmap = BitmapFactory.decodeFile(albumArtFile.getPath(), opt);
            return bitmap == null ? null : getScaledBitmap(bitmap, size);
        }
        return null;
    }

    public static Bitmap getSampledBitmap(byte[] bytes, int size) {
        final BitmapFactory.Options opt = new BitmapFactory.Options();
        opt.inJustDecodeBounds = true;
        BitmapFactory.decodeByteArray(bytes, 0, bytes.length, opt);
        opt.inPurgeable = true;
        opt.inSampleSize = Util.calculateInSampleSize(opt, size, Util.getScaledHeight(opt.outHeight, opt.outWidth, size));
        opt.inJustDecodeBounds = false;
        Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length, opt);
        if (bitmap == null) {
            return null;
        } else {
            return getScaledBitmap(bitmap, size);
        }
    }

    private static Bitmap getScaledBitmap(Bitmap bitmap, int size) {
        // Don't waste time scaling if the difference is minor
        // Large album arts still need to be scaled since displayed as is on now playing!
        if (size < 400 && bitmap.getWidth() < (size * 1.1)) {
            return bitmap;
        } else {
            return Bitmap.createScaledBitmap(bitmap, size, Util.getScaledHeight(bitmap, size), true);
        }
    }

    public static File getAlbumArtDirectory(Context context) {
        File albumArtDir = new File(getSubsonicDirectory(context), "artwork");
        ensureDirectoryExistsAndIsReadWritable(albumArtDir);
        ensureDirectoryExistsAndIsReadWritable(new File(albumArtDir, ".nomedia"));
        return albumArtDir;
    }

    public static File getArtistDirectory(Context context, Artist artist) {
        return new File(getMusicDirectory(context).getPath() + "/" + fileSystemSafe(artist.getName()));
    }

    public static File getArtistDirectory(Context context, MusicDirectory.Entry artist) {
        return new File(getMusicDirectory(context).getPath() + "/" + fileSystemSafe(artist.getTitle()));
    }

    public static File getAlbumDirectory(Context context, MusicDirectory.Entry entry) {
        File dir = null;
        if (entry.getPath() != null) {
            File f = new File(fileSystemSafeDir(entry.getPath()));
            String folder = getMusicDirectory(context).getPath();
            if (entry.isDirectory()) {
                folder += "/" + f.getPath();
            } else if (f.getParent() != null) {
                folder += "/" + f.getParent();
            }
            dir = new File(folder);
        } else {
            MusicDirectory.Entry firstSong;
            if (!Util.isOffline(context)) {
                firstSong = lookupChild(context, entry, false);
                if (firstSong != null) {
                    File songFile = FileUtil.getSongFile(context, firstSong);
                    dir = songFile.getParentFile();
                }
            }

            if (dir == null) {
                String artist = fileSystemSafe(entry.getArtist());
                String album = fileSystemSafe(entry.getAlbum());
                if ("unnamed".equals(album)) {
                    album = fileSystemSafe(entry.getTitle());
                }
                dir = new File(getMusicDirectory(context).getPath() + "/" + artist + "/" + album);
            }
        }
        return dir;
    }

    public static MusicDirectory.Entry lookupChild(Context context, MusicDirectory.Entry entry, boolean allowDir) {
        // Initialize lookupMap if first time called
        String lookupName = Util.getCacheName(context);
        if (entryLookup == null) {
            entryLookup = deserialize(context, lookupName, HashMap.class);

            // Create it if
            if (entryLookup == null) {
                entryLookup = new HashMap<>();
            }
        }

        // Check if this lookup has already been done before
        MusicDirectory.Entry child = entryLookup.get(entry.getId());
        if (child != null) {
            return child;
        }

        // Do a special lookup since 4.7+ doesn't match artist/album to entry.getPath
        String s = Util.getRestUrl(context, null, false, null) + entry.getId();
        String cacheName = "album-" + s.hashCode() + ".ser";
        MusicDirectory entryDir = FileUtil.deserialize(context, cacheName, MusicDirectory.class);

        if (entryDir != null) {
            List<MusicDirectory.Entry> songs = entryDir.getChildren(allowDir, true);
            if (songs.size() > 0) {
                child = songs.get(0);
                entryLookup.put(entry.getId(), child);
                serialize(context, entryLookup, lookupName);
                return child;
            }
        }

        return null;
    }

    public static void createDirectoryForParent(File file) {
        File dir = file.getParentFile();
        if (!dir.exists()) {
            if (!dir.mkdirs()) {
                Log.e(TAG, "Failed to create directory " + dir);
            }
        }
    }

    public static File getSubsonicDirectory(Context context) {
        return context.getExternalFilesDir(null);
    }

    public static File getDefaultMusicDirectory(Context context) {
        if (DEFAULT_MUSIC_DIR == null) {
            File[] dirs;
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                dirs = context.getExternalMediaDirs();
            } else {
                dirs = ContextCompat.getExternalFilesDirs(context, null);
            }

            DEFAULT_MUSIC_DIR = new File(getBestDir(dirs), "music");

            if (!DEFAULT_MUSIC_DIR.exists() && !DEFAULT_MUSIC_DIR.mkdirs()) {
                Log.e(TAG, "Failed to create default dir " + DEFAULT_MUSIC_DIR);

                // Some devices seem to have screwed up the new media directory API.  Go figure.  Try again with standard locations
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                    dirs = ContextCompat.getExternalFilesDirs(context, null);

                    DEFAULT_MUSIC_DIR = new File(getBestDir(dirs), "music");
                    if (!DEFAULT_MUSIC_DIR.exists() && !DEFAULT_MUSIC_DIR.mkdirs()) {
                        Log.e(TAG, "Failed to create default dir " + DEFAULT_MUSIC_DIR);
                    } else {
                        Log.w(TAG, "Stupid OEM's messed up media dir API added in 5.0");
                    }
                }
            }
        }

        return DEFAULT_MUSIC_DIR;
    }

    private static File getBestDir(File[] dirs) {
        // Past 5.0 we can query directly for SD Card
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            for (File dir : dirs) {
                try {
                    if (dir != null && Environment.isExternalStorageRemovable(dir)) {
                        return dir;
                    }
                } catch (Exception e) {
                    Log.e(TAG, "Failed to check if is external", e);
                }
            }
        }

        // Before 5.0, we have to guess.  Most of the time the SD card is last
        for (int i = dirs.length - 1; i >= 0; i--) {
            if (dirs[i] != null) {
                return dirs[i];
            }
        }

        // Should be impossible to be reached
        return dirs[0];
    }

    public static File getMusicDirectory(Context context) {
        String path = Util.getPreferences(context).getString(Constants.PREFERENCES_KEY_CACHE_LOCATION, getDefaultMusicDirectory(context).getPath());
        File dir = new File(path);
        return ensureDirectoryExistsAndIsReadWritable(dir) ? dir : getDefaultMusicDirectory(context);
    }

    public static void deleteMusicDirectory(Context context) {
        File musicDirectory = FileUtil.getMusicDirectory(context);
        MediaStoreService mediaStore = new MediaStoreService(context);
        recursiveDelete(musicDirectory, mediaStore);
    }

    public static void deleteSerializedCache(Context context) {
        for (File file : context.getCacheDir().listFiles()) {
            if (file.getName().contains(".ser")) {
                file.delete();
            }
        }
    }

    public static void deleteArtworkCache(Context context) {
        File artDirectory = FileUtil.getAlbumArtDirectory(context);
        recursiveDelete(artDirectory);
    }

    private static void recursiveDelete(File dir) {
        recursiveDelete(dir, null);
    }

    public static boolean recursiveDelete(File dir, MediaStoreService mediaStore) {
        if (dir != null && dir.exists()) {
            File[] list = dir.listFiles();
            if (list != null) {
                for (File file : list) {
                    if (file.isDirectory()) {
                        if (!recursiveDelete(file, mediaStore)) {
                            return false;
                        }
                    } else if (file.exists()) {
                        if (!file.delete()) {
                            return false;
                        } else if (mediaStore != null) {
                            mediaStore.deleteFromMediaStore(file);
                        }
                    }
                }
            }
            return dir.delete();
        }
        return false;
    }

    public static void deleteEmptyDir(File dir) {
        try {
            File[] children = dir.listFiles();
            if (children == null) {
                return;
            }

            // No songs left in the folder
            if (children.length == 1 && children[0].getPath().equals(FileUtil.getAlbumArtFile(dir).getPath())) {
                Util.delete(children[0]);
                children = dir.listFiles();
            }

            // Delete empty directory
            if (children.length == 0) {
                Util.delete(dir);
            }
        } catch (Exception e) {
            Log.w(TAG, "Error while trying to delete empty dir", e);
        }
    }

    private static boolean ensureDirectoryExistsAndIsReadWritable(File dir) {
        if (dir == null) {
            return false;
        }

        if (dir.exists()) {
            if (!dir.isDirectory()) {
                Log.w(TAG, dir + " exists but is not a directory.");
                return false;
            }
        } else {
            if (dir.mkdirs()) {
                Log.i(TAG, "Created directory " + dir);
            } else {
                Log.w(TAG, "Failed to create directory " + dir);
                return false;
            }
        }

        if (!dir.canRead()) {
            Log.w(TAG, "No read permission for directory " + dir);
            return false;
        }

        if (!dir.canWrite()) {
            Log.w(TAG, "No write permission for directory " + dir);
            return false;
        }
        return true;
    }

    public static boolean verifyCanWrite(File dir) {
        if (ensureDirectoryExistsAndIsReadWritable(dir)) {
            try {
                File tmp = new File(dir, "checkWrite");
                tmp.createNewFile();
                if (tmp.exists()) {
                    if (tmp.delete()) {
                        return true;
                    } else {
                        Log.w(TAG, "Failed to delete temp file, retrying");

                        // This should never be reached since this is a file Audinaut created!
                        Thread.sleep(100L);
                        tmp = new File(dir, "checkWrite");
                        if (tmp.delete()) {
                            return true;
                        } else {
                            Log.w(TAG, "Failed retry to delete temp file");
                            return false;
                        }
                    }
                } else {
                    Log.w(TAG, "Temp file does not actually exist");
                    return false;
                }
            } catch (Exception e) {
                Log.w(TAG, "Failed to create tmp file", e);
                return false;
            }
        } else {
            return false;
        }
    }

    /**
     * Makes a given filename safe by replacing special characters like slashes ("/" and "\")
     * with dashes ("-").
     *
     * @param filename The filename in question.
     * @return The filename with special characters replaced by hyphens.
     */
    private static String fileSystemSafe(String filename) {
        if (filename == null || filename.trim().length() == 0) {
            return "unnamed";
        }

        for (String s : FILE_SYSTEM_UNSAFE) {
            filename = filename.replace(s, "-");
        }
        return filename;
    }

    /**
     * Makes a given filename safe by replacing special characters like colons (":")
     * with dashes ("-").
     *
     * @param path The path of the directory in question.
     * @return The the directory name with special characters replaced by hyphens.
     */
    private static String fileSystemSafeDir(String path) {
        if (path == null || path.trim().length() == 0) {
            return "";
        }

        for (String s : FILE_SYSTEM_UNSAFE_DIR) {
            path = path.replace(s, "-");
        }
        return path;
    }

    /**
     * Similar to {@link File#listFiles()}, but returns a sorted set.
     * Never returns {@code null}, instead a warning is logged, and an empty set is returned.
     */
    public static SortedSet<File> listFiles(File dir) {
        File[] files = dir.listFiles();
        if (files == null) {
            Log.w(TAG, "Failed to list children for " + dir.getPath());
            return new TreeSet<>();
        }

        return new TreeSet<>(Arrays.asList(files));
    }

    public static SortedSet<File> listMediaFiles(File dir) {
        SortedSet<File> files = listFiles(dir);
        Iterator<File> iterator = files.iterator();
        while (iterator.hasNext()) {
            File file = iterator.next();
            if (!file.isDirectory() && !isMediaFile(file)) {
                iterator.remove();
            }
        }
        return files;
    }

    private static boolean isMediaFile(File file) {
        String extension = getExtension(file.getName());
        return MUSIC_FILE_EXTENSIONS.contains(extension);
    }

    public static boolean isPlaylistFile(File file) {
        String extension = getExtension(file.getName());
        return PLAYLIST_FILE_EXTENSIONS.contains(extension);
    }

    /**
     * Returns the extension (the substring after the last dot) of the given file. The dot
     * is not included in the returned extension.
     *
     * @param name The filename in question.
     * @return The extension, or an empty string if no extension is found.
     */
    public static String getExtension(String name) {
        int index = name.lastIndexOf('.');
        return index == -1 ? "" : name.substring(index + 1).toLowerCase();
    }

    /**
     * Returns the base name (the substring before the last dot) of the given file. The dot
     * is not included in the returned basename.
     *
     * @param name The filename in question.
     * @return The base name, or an empty string if no basename is found.
     */
    public static String getBaseName(String name) {
        int index = name.lastIndexOf('.');
        return index == -1 ? name : name.substring(0, index);
    }

    public static <T extends Serializable> void serialize(Context context, T obj, String fileName) {
        Output out = null;
        try {
            RandomAccessFile file = new RandomAccessFile(context.getCacheDir() + "/" + fileName, "rw");
            out = new Output(new FileOutputStream(file.getFD()));
            synchronized (kryo) {
                kryo.writeObject(out, obj);
            }
        } catch (Throwable x) {
            Log.w(TAG, "Failed to serialize object to " + fileName);
        } finally {
            Util.close(out);
        }
    }

    public static <T extends Serializable> T deserialize(Context context, String fileName, Class<T> tClass) {
        Input in = null;
        try {
            File file = new File(context.getCacheDir(), fileName);
            if (!file.exists()) {
                return null;
            }

            RandomAccessFile randomFile = new RandomAccessFile(file, "r");

            in = new Input(new FileInputStream(randomFile.getFD()));
            synchronized (kryo) {
                return kryo.readObject(in, tClass);
            }
        } catch (FileNotFoundException e) {
            // Different error message
            Log.w(TAG, "No serialization for object from " + fileName);
            return null;
        } catch (Throwable x) {
            Log.w(TAG, "Failed to deserialize object from " + fileName);
            return null;
        } finally {
            Util.close(in);
        }
    }

    public static <T extends Serializable> void serializeCompressed(Context context, T obj, String fileName) {
        Output out = null;
        try {
            RandomAccessFile file = new RandomAccessFile(context.getCacheDir() + "/" + fileName, "rw");
            out = new Output(new DeflaterOutputStream(new FileOutputStream(file.getFD())));
            synchronized (kryo) {
                kryo.writeObject(out, obj);
            }
        } catch (Throwable x) {
            Log.w(TAG, "Failed to serialize compressed object to " + fileName);
        } finally {
            Util.close(out);
        }
    }

    public static <T extends Serializable> T deserializeCompressed(Context context, String fileName, Class<T> tClass) {
        Input in = null;
        try {
            RandomAccessFile file = new RandomAccessFile(context.getCacheDir() + "/" + fileName, "r");

            in = new Input(new InflaterInputStream(new FileInputStream(file.getFD())));
            synchronized (kryo) {
                return kryo.readObject(in, tClass);
            }
        } catch (FileNotFoundException e) {
            // Different error message
            Log.w(TAG, "No serialization compressed for object from " + fileName);
            return null;
        } catch (Throwable x) {
            Log.w(TAG, "Failed to deserialize compressed object from " + fileName);
            return null;
        } finally {
            Util.close(in);
        }
    }
}
